Almost all jurisdictions only allow 180 days to complete the work or to begin work under an approved building permit.
Most jurisdictions require you to renew the permit prior to the expiration date or you must pay a new application fee.
Some jurisdictions are a little more flexible but it is your responsibility to make sure to renew. We saw an applicant last week have to refile because he was more than 30 days past the expiration.
His cost? $3300.